The images in the Dental Research Photographic Collection are in the public domain and are not subject to copyright in the United States. However, please pay special attention to the individual works to make sure there are no copyright restrictions indicated. Individual works may require securing other permissions from the original copyright holder. Use of the images from NIST Digital Collections is not restricted, but a statement of attribution is required. Please use the following attribution statement: ""National Institute of Standards and Technology Digital Collections, Gaithersburg, MD 20899.""